1、提示并输入一个字符串，统计该字符中大写、小写字母个数、数字个数、空格个数以及其他字符个数（要求使用C++风格字符串完成）

#include <iostream>

using namespace std;

int main()
{
    string str;
    cout << "please enter str:" << endl;
    getline(cin,str);
    int capital=0,lowercase=0,num=0,space=0,other=0;
    for(size_t i=0;i<str.size();i++)
    {
        if('A'<=str[i] && 'Z'>=str[i])
        {
            capital+=1;
        }
        else if('a'<=str[i] && 'z'>=str[i])
        {
            lowercase+=1;
        }
        else if('0'<=str[i] && '9'>=str[i])
        {
            num+=1;
        }
        else if(str[i] == ' ')
        {
            space+=1;
        }
        else
        {
            other+=1;
        }
    }
    cout << "capital= " << capital << endl;
    cout << "lowercase= " << lowercase << endl;
    cout << "num= " << num << endl;
    cout << "space= " << space << endl;
    cout << "other= " << other << endl;
    return 0;
}

2、思维导图